When it hits the fan... groundwater quality and public health

Mark Borchardt is the DIrector of the Laboratory for Infectious Disease and the Environment, USGS.  He has been studying the microbes that contaminate Wisconsin's groundwater, and the impact they have on the health of the people of Wisconsin. He told us that it is important to understand that poop is very political.  The two big sources of fecal contamination in water are cows and people, and fecal organisms are found in water throughout Wisconsin.   Is this a health risk or a non-issue?  

The second marks below can be used to navigate to specific elements of Mark's talk in this summary:  

7:30  The Laboratory conducted a study to determine how many people are getting sick from drinking non-chlorinated municipal water.  This was the WAHTER study, back in 2007-8. ( Click here for more information. ).  They correlated the presence of pathogens in water to the incidence of acute gastrointestinal disease.   The incidence of disease far surpasses the ‘allowable’ level of disease due to water borne illness that has been set by US EPA.   People who drink water from non-disinfected public water supplies or private wells are much more susceptible to water-borne disease than people whose water is disinfected.  
 
21:00  Based on this study, Wisconsin passed a law requiring all water supplies be disinfected.  However, after political change in state government, a law was passed that prohibits DNR from requiring disinfection. 
 
25:00   The septic system at a restaurant in Door County was causing illness.  It was a new system; how could this be happening?  The answer was that there was a broken seal in the tank that was causing part of the problem, but the other part of the problem was that the bedrock in the area is fractured dolomite which quickly spreads contamination over great distances.   Mark's talk tracks the movement of contaminants through the groundwater to neighboring residential wells.  
 
29:40   Kewaunee County still has “brown water events” in the spring and fall that are clearly linked with intestinal disease.  Genetic testing has traced the fecal organisms back to both humans and cattle, and this area has a very large number of Combined Animal Feeding Operations (CAFOs).  The cattle-source organisms probably spike when manure is being applied, but the human-source organisms are present year round due to the widespread use of septic systems in the area.  (  Click here for more information.  In this article, one participant asked whether dispensing less liquid manure would reduce well contamination. “You don’t need a scientist for that one,” Borchardt answered. “If you remove the fecal source, you remove the contamination.” ​ )